Step 1. Get into the game and find your INBOX.
Step 2. Open INBOX and find INVITE icon.
Step 3. Get into INVITE page and choose a way to share.
Click SHARE to create a link that you can copy-paste to anywhere you would like to share at.
Click INVITE to share the link directly via Messenger (There will be a window pops up when you do not have Messenger installed).
The progress bar will be updated when your friends join the game via the link you shared, you can win the corresponding rewards when the bar is filled up.
The friends joined will also be added to your friend list automatically.